Product manual

SPECIFICATION

• product name：	Environmental air quality detector
  Model：	MAQ01020406070914-S-P4
  version：	V1.0
  Creator：	He Genwen
  reviewed by：	Yuan Chao

   

  1、DESCRIPTION

  The Environmental Air Quality Detection Module MAQ01020406070914-S-P4 is a digital signal output multi parameter sensor product that integrates temperature, humidity, CO2, PM2.5, PM10, TVOC, and formaldehyde detection. It uses high-performance sensors and control chips, with high accuracy and good stability. The equipment adopts a wide voltage DC12~24V power supply, RS485 signal output, standard Modbus RTU communication protocol, communication address can be set, and baud rate can be changed. Widely used in locomotivesAir conditioning, building HVAC, building energy efficiency, smart home, schools, hospitals, airport stations and other places。

   

  2、Functional characteristics

  1、    Adopting isolated RS485 circuit for stable communication。

  2、    Adopting aluminum alloy shell, suitable for various installation methods。

  3、    It can simultaneously measure multiple parameters such as temperature, humidity, CO2, PM2.5, PM10, TVOC, and formaldehyde, and can expand more air quality parameters。

   

  3、TECHNICAL INDEX

  Working temperature range	0 ~50℃
  Operating humidity range	0~95% RH (non condensation)
  Storage temperature range	-40 ~50℃
  power input	DC 12~24V
  maximum operating current	≤ 100mA  ( DC24V)
  OUTPUT	Modbus RTU, start bit 1, data bit 8, stop bit 1, no parity check, baud rate 9600bps (default)
  Warm-up time	2 minutes (formaldehyde and TVOC need to be preheated and stabilized, other parameters will be displayed when powered on)
  Installation method	Ceiling installation and wall mounted installation
  Product weight	465 grams

  Product size

  188.0mm×114.5mm×33.0mm

   

  4、Detection parameters

  Testing items	detection range	check the accuracy	Detection Principle
  temperature	-40~125℃	±0.5℃ (@25℃)  ，± 1℃ (full scale)	MEMS devices
  humidity	0~ 100%RH	± 3%RH(@25℃ ，  30%~80%RH； other±5%RH)	MEMS devices
  CO2	400~5000ppm	± (75ppm + 5% of reading )	NDIR Non dispersed infrared sensor
  PM2.5	0 ~1000µg/m3	± 10%(@100~500μg/m3 );     ± 10μg/m3 (@ 0 ~100μg/m3 )	Laser scattering
  PM10	0 ~1000µg/m3	± 10%(@100~500μg/m3 );    ± 10μg/m3(@ 0 ~100μg/m3 )	Laser scattering
  TVOC	0 ~2000ppb	± 30%FS@25℃	semiconductor gas sensor
  formaldehyde	0 ~1000ppb	± 15%FS@25℃	Fuel cell sensors

  notes：

  1、The above detection accuracy was measured under the following environmental conditions: temperature of 25 ℃, relative humidity of 50% RH, and 1 atmospheric pressure. The maximum test item to be tested does not exceed the detection range.

  2、In order to continuously improve the product, our company reserves the right to change the design features and specifications.

  5、Product size

  

  6、Wiring Instructions

  

  1、  +12~24V；    

  2、GND；   

  3、  RS485A；   

  4、  RS485B；  

  5、GND1；

  When wiring a circuit, connect the wires to the wiring terminals to ensure that the wiring is correct and firm。

   

   

  7、note

• 1. Preheat for at least 2 minutes when using power on.

• 2. Install the module in the location where it needs to be tested, away from heat sources.

• 3. Do not place the module in high concentration organic gases or corrosive gases for a long time.

• 4. Do not install the module for use in strong convective gas environments.

• 5. Avoid large dust particles such as ground dust, floating debris, and even flocculent pollution that may cause fan entanglement and obstruction.

• 6. Do not disassemble the sensor to prevent irreversible damage.

• 7. The RS485 communication line requires shielded twisted pair cables, and if necessary, two 250 Ω terminals with matching resistors are required.

• 8. The usage environment should be free of conductive dust, corrosive metals, and gases that damage insulation, avoiding direct sunlight and rain.

• 9. Avoid placing the module in a salt spray, acidic or oxidizing gas environment (such as sulfur dioxide, hydrochloric acid, etc.).

• 8. RS485 communication protocol

• 1. Overview

• The communication protocol provides a detailed description of the input and output commands, information, and data of the environmental air quality detection module for third-party use and development.

• This product adopts a standard serial RS485 communication interface, and the information transmission method is asynchronous. The start bit is 1 bit, the data bit is 8 bits, and the stop bit is 1 bit. There is no parity check (switching through instructions); The baud rate is 9600bps (default) and can be modified through instructions; The default factory address value for the device is 01, and the range of address values that can be set is 01 to 255; The terminal resistance can be configured to 120 ohms, and can be switched to 120 ohms in the form of a toggle switch.

• 2. Detailed communication protocol

• 2.1 Communication methods

• (1) All loop communication should follow the master/slave mode, and data should be transmitted between the master and slave stations.

• (2) If the master station or any slave station receives a package containing an unknown command, the package will be ignored and the receiving station will not respond.

2.2 Return data frame structure description

3、transport format

3.1 Host sends read address command (one-to-one)：

Slave return address：

Example：

Host sending：  00 03 01 00 00 01 84 27

Slave response: 00 03 02 00 address CRCL CRCH; If the address is 2, the read sensor address is 2

3.2 Host sends read data command：

At present, only simultaneous reading of all data is supported, starting from address 0x0002, reading 7 data values. 7 sensor data correspond to 7 sensor addresses, and the high bit of the starting address is always 0, while the high bit of the number of returned data is always 0.

Slave return value：

Return Format：

Return data content：

Example：

Host sending: 01 03 00 02 00 07 CRCL CRCH

Slave response: 01 03 0E 02 26 00 26 00 34 00 0E 00 11 00 FF 03 11 CRCL CRCH

Note: Data return calculation

1. CO2 data: 0x0226, corresponding to a decimal value of 550, indicating a CO2 concentration of 550ppm;

2. Formaldehyde data: 0x0026, corresponding to a decimal system of 38, indicating a formaldehyde concentration of 38 ppb;

3. TVOC data: 0x0034, corresponding to decimal 52, indicating a TVOC concentration of 52 ppb;

4. PM2.5 data: 0x000E, corresponding to decimal 14, indicating a PM2.5 particle concentration of 14ug/m ³；

5. PM10 data: 0x0011, corresponding to decimal 17, indicating a PM10 particle concentration of 17ug/m ³；

6. Temperature data: 0x00FF, corresponding to decimal 255, represents a temperature of 25.5 ℃ (negative temperature is represented by complement);

7. Humidity data: 0x0311, corresponding to decimal 785, indicating a humidity of 78.5% RH;

3.3 Set Address Command (one-on-one):

This command can set the address of the slave, with address values ranging from 01 to 255 (factory default is 01).

Host sends instructions:

Slave response:

Example：

Host sending: 00 06 01 00 00 address CRCL CRCH

Slave response: 00 06 02 00 address CRCL CRCH

If the address is 2, set the slave address to 2; After receiving a response from the slave, the host successfully set the address.

3.4 Setting Baud Rate

The default baud rate of this product is 9600bps, and the available updated baud rates (in bps) include 4800, 9600, 11400, 19200, 38400, 57600, and 115200; These baud rates correspond to 1, 2, 3, 4, 5, 6, and 7 in the instruction.

Set baud rate format:

Example：

Host sending: 01 06 00 FD 00 04 CRCL CRCH

Slave response: None

Change the baud rate of the device with address 01 to 04, that is, change the baud rate to 19200.

3.5 Switching formats without checksum and even verification

00: represents no checksum, 01 represents even checksum

Example:

Host sending: 01 06 00 FE 00 01 CRCL CRCH

Slave response: None

Change the verification method of the device with address 01 to even verification.

4. Host data sampling frequency:

The interval between reading data from the upper computer should not be less than 500ms, with a recommended value of 1s or more.

5. CRC verification reference:

unsigned int GetCRC16(unsigned char *ptr,   unsigned char len)

{

unsigned int index;

unsigned char crch = 0xFF;   //High CRC bytes

unsigned char crcl = 0xFF;   //Low CRC byte

unsigned char code TabH[] = {   //CRC High byte value table

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,

0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,

0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,

0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,

0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,

0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,

0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,

0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,

0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,

0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,

0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x00, 0xC1, 0x81, 0x40,

0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1,

0x81, 0x40, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41,

0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0,

0x80, 0x41, 0x00, 0xC1, 0x81, 0x40

} ;

unsigned char code TabL[] = {   //CRC Low byte value table

0x00, 0xC0, 0xC1, 0x01, 0xC3, 0x03, 0x02, 0xC2, 0xC6, 0x06,

0x07, 0xC7, 0x05, 0xC5, 0xC4, 0x04, 0xCC, 0x0C, 0x0D, 0xCD,

0x0F, 0xCF, 0xCE, 0x0E, 0x0A, 0xCA, 0xCB, 0x0B, 0xC9, 0x09,

0x08, 0xC8, 0xD8, 0x18, 0x19, 0xD9, 0x1B, 0xDB, 0xDA, 0x1A,

0x1E, 0xDE, 0xDF, 0x1F, 0xDD, 0x1D, 0x1C, 0xDC, 0x14, 0xD4,

0xD5, 0x15, 0xD7, 0x17, 0x16, 0xD6, 0xD2, 0x12, 0x13, 0xD3,

0x11, 0xD1, 0xD0, 0x10, 0xF0, 0x30, 0x31, 0xF1, 0x33, 0xF3,

0xF2, 0x32, 0x36, 0xF6, 0xF7, 0x37, 0xF5, 0x35, 0x34, 0xF4,

0x3C, 0xFC, 0xFD, 0x3D, 0xFF, 0x3F, 0x3E, 0xFE, 0xFA, 0x3A,

0x3B, 0xFB, 0x39, 0xF9, 0xF8, 0x38, 0x28, 0xE8, 0xE9, 0x29,

0xEB, 0x2B, 0x2A, 0xEA, 0xEE, 0x2E, 0x2F, 0xEF, 0x2D, 0xED,

0xEC, 0x2C, 0xE4, 0x24, 0x25, 0xE5, 0x27, 0xE7, 0xE6, 0x26,

0x22, 0xE2, 0xE3, 0x23, 0xE1, 0x21, 0x20, 0xE0, 0xA0, 0x60,

0x61, 0xA1, 0x63, 0xA3, 0xA2, 0x62, 0x66, 0xA6, 0xA7, 0x67,

0xA5, 0x65, 0x64, 0xA4, 0x6C, 0xAC, 0xAD, 0x6D, 0xAF, 0x6F,

0x6E, 0xAE, 0xAA, 0x6A, 0x6B, 0xAB, 0x69, 0xA9, 0xA8, 0x68,

0x78, 0xB8, 0xB9, 0x79, 0xBB, 0x7B, 0x7A, 0xBA, 0xBE, 0x7E,

0x7F, 0xBF, 0x7D, 0xBD, 0xBC, 0x7C, 0xB4, 0x74, 0x75, 0xB5,

0x77, 0xB7, 0xB6, 0x76, 0x72, 0xB2, 0xB3, 0x73, 0xB1, 0x71,

0x70, 0xB0, 0x50, 0x90, 0x91, 0x51, 0x93, 0x53, 0x52, 0x92,

0x96, 0x56, 0x57, 0x97, 0x55, 0x95, 0x94, 0x54, 0x9C, 0x5C,

0x5D, 0x9D, 0x5F, 0x9F, 0x9E, 0x5E, 0x5A, 0x9A, 0x9B, 0x5B,

0x99, 0x59, 0x58, 0x98, 0x88, 0x48, 0x49, 0x89, 0x4B, 0x8B,

0x8A, 0x4A, 0x4E, 0x8E, 0x8F, 0x4F, 0x8D, 0x4D, 0x4C, 0x8C,

0x44, 0x84, 0x85, 0x45, 0x87, 0x47, 0x46, 0x86, 0x82, 0x42,

0x43, 0x83, 0x41, 0x81, 0x80, 0x40

} ;

while (len--)   //Calculate the specified length CRC

{

index = crch ^ *ptr++;

crch = crcl ^ TabH[ index];

crcl = TabL[ index];

}

return ((crch<<8) | crcl);

}